Guarantee on basis of actual constituents: —
Nitrogen (total) ............1.65 to 2.50 per cent.
Phosphoric acid (available).........7.00 to 9.00 per cent.
Potash (actual).............3.25 to 4.25 per cent.
It will be observed that the guarantee in the one case means the same as in the other. Different methods of stating guarantees should not mislead those who will familiarize themselves with the terms used, and with the conversion factors.
In the case of the mixed fertilizers, the percentage of the constituent elements that are given on the basis of equivalents represents the amounts when they exist in combination with other elements, viz., nitrogen, as ammonia; phosphoric acid, as bone phosphate; and potash, as sulfate.
The trade-values in the following schedule have been agreed upon by the Experiment Stations of Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Vermont, as a result of study of the prices actually prevailing in the large markets of these states.
These trade-values represent, as nearly as can be estimated, the average prices at which, during the six months preceding March, the respective ingredients, in the form of unmixed raw materials, could be bought at retail for cash in our large markets. These prices also correspond (except in case of available phosphoric acid) to the average wholesale prices for the six months preceding March, plus about 20 per cent in case of goods for which there are wholesale quotations.
Valuation and cost of fertilizers.
The total cost (to the farmer) of a ton of commercial fertilizer may be regarded as consisting of the following elements: (1) Retail cash cost, in the market, of unmixed trade materials; (2) cost of mixing; (3) cost of transportation; (4) storage, commissions to agents and dealers, selling on long credit, bad debts, etc. While the total cost of a fertilizer is made up of several different elements, a commercial valuation includes only the first of the elements entering into the total cost, that is, the retail cash cost in the market of unmixed raw materials.
Valuation, and agricultural value.
The agricultural value of a fertilizer depends upon its crop-producing power. A commercial valuation does not necessarily have any relation to crop-producing value on a given farm. For a particular soil and crop, a fertilizer of comparatively low commercial valuation may have a higher agricultural value; while, for another crop on the same soil, or the same crop on another soil, the reverse might be true.
Rule for calculating approximate commercial valuation of mixed fertilizers on basis of trade-values for 1910.
Multiply the percentage of nitrogen by 4.0. Multiply the percentage of available phosphoric acid by 0.8. Multiply the percentage of insoluble phosphoric acid (total minus available) by 0.4.
Multiply the percentage of potash by 1.0.
The sum of these 4 products will be the commercial valuation per ton on the basis taken.
Illustration. The table of analyses shows a certain fertilizer to have the following composition: Nitrogen 2.52 per cent; available phosphoric acid 6.31 per cent; insoluble phosphoric acid .89 per cent; potash 6.64 per cent. According to this method of valuation, the computation would be as follows: —
Nitrogen................ 2.52 X 4.0 = $10.08
Available phosphoric acid .......... 6.31 X 0.8 = 5.05
Insoluble phosphoric acid .......... 0.89 X 0.4 = 0.36
Potash................. 6.64 X 1.0 = 6.64 $22.13
This rule assumes allthe nitrogen to be organic and all the potash to be in the form of sulfate. If a considerable portion of nitrogen exists in the fertilizer as nitrate of soda or as sulfate of ammonia, and potash is present as muriate, the results are somewhat less.